Heat shock transcription factor 1 localizes to sex chromatin during meiotic repression.

Heat shock factor 1 (HSF1) is an important transcription factor in cellular stress responses, cancer, aging, and developmental processes including gametogenesis. Disruption of Hsf1, together with another HSF family member, Hsf2, causes male sterility and complete lack of mature sperm in mice, but the specific role of HSF1 in spermatogenesis has remained unclear. Here, we show that HSF1 is transiently expressed in meiotic spermatocytes and haploid round spermatids in mouse testis.

Mouse heat-shock factor 1 (HSF1) is involved in testicular response to genotoxic stress induced by doxorubicin.

Heat-shock factor 1 (HSF1) protects cells and organisms against various types of stress, either by triggering a complex response that promotes cell survival or by triggering cell death when stress-induced alterations cannot be rescued. Although this dual role of HSF1 was observed in spermatogenesis exposed to heat shock or proteotoxic stress, HSF1 was also reported to contribute to cell resistance against genotoxic stress, such as that caused by doxorubicin, an anticancer drug in common clinical use. To better understand the stress/cell-dependent functions of HSF1, we used wild-type and Hsf1(tm1Ijb)/Hsf1(tm1Ijb) males to determine the role of HSF1 in the genotoxic stress response elicited in spermatogenic cells.

Multistress regulation in Escherichia coli: expression of osmB involves two independent promoters responding either to sigmaS or to the RcsCDB His-Asp phosphorelay.

Transcription of the Escherichia coli osmB gene is induced by several stress conditions. osmB is expressed from two promoters, osmBp1 and osmBp2. The downstream promoter, osmBp2, is induced after osmotic shock or upon entry into stationary phase in a sigma(S)-dependent manner.

Plasmid DNA supercoiling and survival in long-term cultures of Escherichia coli: role of NaCl.

The relationship between the survival of Escherichia coli during long-term starvation in rich medium and the supercoiling of a reporter plasmid (pBR322) has been studied. In aerated continuously shaken cultures, E. coli lost the ability to form colonies earlier in rich NaCl-free Luria-Bertani medium than in NaCl-containing medium, and the negative supercoiling of plasmid pBR322 declined more rapidly in the absence of NaCl.

NhaR and RcsB independently regulate the osmCp1 promoter of Escherichia coli at overlapping regulatory sites.

Transcription of the Escherichia coli osmC gene is induced by several stress conditions. osmC is expressed from two overlapping promoters, osmCp1 and osmCp2. The proximal promoter, osmCp2, is transcribed at the entry into the stationary phase by the sigma(s) sigma factor.